Inherent heterogeneity and distribution of knowledge strongly prevent knowledge from sharing and reusing among different agents and across different domains; formal ontologies have been viewed as a promising means to tackle this problem. In this paper, we present a domain-specific formal ontology for archaeological knowledge sharing and reusing. The ontology consists of three major parts: archaeological categories, their relationships and axioms. The ontology not only captures the semantics of archaeological knowledge, but also provides archaeology with an explicit and formal specification of a shared conceptualization, thus making archaeological knowledge shareable and reusable across humans and machines in a structured fashion. As an application of the ontology, we have developed an ontology-driven approach to knowledge acquisition from archaeological text.